DE926404C - Chuck - Google Patents

Description

(WiGBl. P. 175)

ISSUED APRIL 18, 1955

L 10878 Ib 14p a

Chuck

It is known that in machine tools for achieving high working speeds Use of chucks is required that are clamped and clamped while the machine is in operation can be relaxed. This is how the machine tool is turned off caused loss of time and also a considerable loss of energy caused by the Restart of the electric motors occurs.

There are already known chucks in which the clamping of the workpiece to be machined is obtained by means of a body which is displaceable in the axial direction and which is opposite to the axial direction inclined surfaces or ramps is provided on the one ends of double-armed lever act, which are fixed with respect to the chuck, tangential to the direction of rotation Axes are pivotable and the other ends of the clamping jaws for the workpiece are radial move. With these chucks, the workpiece is released by springs, which pivot the levers in the opposite direction to the movement imparted to them by the ramps.

Such chucks have several disadvantages. The main disadvantage is that it is only with them it is possible to clamp the workpiece to be machined from the outside. Such chucks can cannot be used to clamp tubular workpieces from the inside. The jaws can only exert their clamping movement in the direction in which they are driven by the ramps to be brought. In addition, the through

such chucks obtained tension less effectively because a significant portion of the tension force would be obtained is used to stretch the springs.

The main purpose of the invention is to avoid these drawbacks.

According to the invention, the axially displaceable body with respect to the chuck axis inclined breakthroughs preferably of rectangular cross-section, their to ίο Direction of rotation of tangential boundary walls form parallel opposite ramps, between and opposite which sliding pieces move, which articulately engage the levers for actuating the clamping jaws.

In this way the levers and consequently the clamping jaws are adjusted according to the direction of displacement of the longitudinally displaceable body inevitably and positively either in one or the other direction, which makes it possible to selectively move workpieces from the inside or to be clamped from the outside.

In addition, the clamping force is increased both in one and in the other clamping direction transferred to the jaws alone, which makes it possible to obtain a very effective tension. The relaxation is obtained by reversing the longitudinally accidental body Direction is shifted, wherein the relaxation, d. H. moving the clamping jaws in the opposite one Direction by which the ramp opposite the ramp used for tensioning is ensured.

With the same amount of movement of the axially movable body, the amplitude of movement depends on Clamping members obviously on the one hand from the relative length of the lever and on the other hand from the slope of the ramps. If this inclination is great, so is the amplitude of the movement Clamping organ large, while those exerted in a certain, on the axially movable body Thrust achieved clamping force is relatively low. However, if the inclination is small, the clamping force can be quite large, while the movement of the clamping member is much less. In any case, it is advisable to use a ramp slope that is smaller than the angle of friction so that the sliding block after tensioning clamps on the ramp without it being necessary to act on the axially movable body To maintain thrust. In this way, a permanent axial thrust is applied to the Spindle avoided.

To avoid the need for a relatively large radial movement of the clamping elements the need for a strong clamping force at the end of the stroke of the axially movable body in To bring harmony, it is advantageous to use the Lever arranged sliding block to manufacture from two parts, one of which has a strong inclination has and cooperates directly with the ramp of the axially movable body, while the other on hinged to the lever and sliding in the first part, has a slight inclination, both of which Parts are connected by an elastic organ that constantly strives to connect the two parts with To keep relation to each other in their middle position. Therefore, when moving the axially movable Body for clamping a workpiece to clamp the clamping organs frantically Workpiece approximated, since here the part formed with a steep incline in the recess of the axially movable body slides. When the clamping elements come to rest on the workpiece is the force resulting from the thrust exerted on the axially movable body greater than the elastic force that holds the two parts in their central position, so that the second part slides in the first, which ensures that the clamping force becomes effective. This tension effect remains due to the jamming of the two parts and the common Clamping the two parts with the ramp of the axially movable body is effective.

When relaxing, the clamping effect is first removed on the steeply inclined ramp, see above that the second part is released and the elastic member with respect to the second part returns the first to its middle position.

The invention is described with reference to the drawings, for example.

Fig. Ι shows a section guided essentially in an axial plane through a chuck according to the invention, the section being taken along the line I-I of Fig. 2;

Fig. 2 shows a section along the line H-II Fig. 1, with various parts omitted and removed;

Fig. 3 shows a front view of the chuck with various organs omitted;

Fig. 4 shows a section along the line IV-IV of Fig. 1;

Fig. 5 shows a section through the axis of the chuck with another embodiment of the lever and the sliding blocks;

Fig. 6 shows a section along the line VI-VI

Fig. S; -

Fig. 7 shows a section along the line VII-VIT of Fig. 6;

Fig. 8 shows a partial section along the line VIII-VIII of Fig. 2;

Fig. 9 is a simplified front view of the chuck showing the arrangement of an axial Stop in same shows;

Fig. 10 shows a section along the line X-X of Fig. 9;

Fig. 11 shows a detail of the especially for the chuck according to the invention suitable clamping members;

Fig. 12 shows a section along the line XII-XII in Fig. 11;

Fig. 13 shows an axial section of the central part of the chuck with the arrangement of a "rod guide tube inside it;

Fig. 14 shows partly in elevation, and partly in section a key suitable for adjusting the chuck according to the invention.

The chuck shown in its entirety in Fig. Ί, 2 and 3 is arranged on the hollow spindle 1 of a machine tool. As usual, the spindle nose is designed with a frustoconical part i ^a which protrudes beyond the spindle flange. The bottom 2 of the chuck, which is essentially disk-shaped and is recessed in its center, is pushed onto the frustoconical part and thus centered. The one-piece body 3 of the chuck has a front part 3 °, which is also disc-shaped and in its dimensions approximately corresponds to the floor, while it is formed backwards, ie in the direction of the spindle nose, with three segment bodies 3 ^& , which have a Shoulder of the bottom 2 to be pushed. The free space in the form of a three-armed star that is limited in the body of the chuck is taken up by the correspondingly designed, axially movable body (organ 4), the arms of which can slide ^{on the smooth side surfaces 5 of the segments 3 and 3.}

The circumference of the chuck is closed by a cylindrical ring 6 which is arranged between the base 2 and the body 3. In the same way, the inner circumference of the chuck is closed by a ring 7. This ring 7 is formed with elongated holes J ^a extending in the axial direction, through which the fingers 8 penetrating the part 4 and ^{supporting on the segments 3 and 3 extend.} The ends of the fingers 8 enter the groove g ^{a of} a threaded sleeve 9 that can slide inside the ring 7. The end of a tube 10, which is secured by a lock nut 11, is screwed into the threaded sleeve. The tube 10 rotates with the spindle of the machine, passes through the spindle from one end to the other and can be operated by any movable means operating on its opposite end, not shown. In order to keep the axial bore of the spindle free, the force exerted on the pipe 10 is preferably carried out on its outer circumference. As it moves, the tube 10 takes the sleeve 9 with it, which in turn effects the axial movement of the organ 4 by means of the fingers 8.

The component described above with its individual parts is held together by means of bolts 12 (Fig. 8) , by means of which the base 2 is attached to the segment bodies 3 *. The chuck is fastened to the spindle nose by bolts 13, which pass through the segment body and are screwed into the fastening flange of the spindle.

Each of the arms of the star-shaped organ 4 consists of two parts which are held together by bolts 14. Each of these arms has an opening (recess 15) of rectangular cross-section, the inner and outer boundary surfaces i5 are parallel ^fl and 15 ^"6 and lie in inclined planes. In these recesses, sliding blocks 16 (which Primärgleitsteine) slidably disposed whose cross-section in the described embodiment is substantially U-shaped, with the inner surfaces of the legs of the u inclined parallel planes i6 ^a * form and 16 whose inclination is smaller with respect to the axis of the chuck than the planes 15. in the recess of each of the sliding blocks 16 a secondary sliding block 17 is arranged, which is connected to the end of a lever 19 by means of a sleeve 18. A cone-head bolt 20, which is subjected to the pressure of a spring 21, is slidably arranged in the bore of the sleeve Spring formed by one on top of the other spring washers In the rest position the end of the bolt 20 is conical n seat 22 of sliding block 16.

In the embodiment shown in FIGS. 1, 2 and 4, the arm of the lever 19 which can pivot about the sleeve 18 is in one piece and asymmetrical, which can result in this lever being subjected to torsional stresses. This can be avoided in the manner shown in Figs. In this case, the lever 19 ° consists of two arms Ig ₁ and I9 ₂ , which encompass the sliding blocks 16 and 17. The primary sliding block 16 is provided with an elongated hole i6 ^a through which the sleeve 18 passes. This elongated hole enables the sliding blocks 16 and 17 to move relative to one another. Axial movements of the sleeve 18 are prevented by a locking finger 50 loaded by the spring 51, the locking finger and the spring being arranged in the secondary sliding block 17. The spring 51 is supported against a plug 52 held by a pin 53.

The elastic member, which tends to keep the two sliding blocks with respect to each other in their central position, consists of a finger ¹ QQ 2o ^a (Fig. 5), which is arranged in a bore 55 of the sliding block 17, this bore being perpendicular to the ramps on the sliding blocks 16 and 17 is arranged. The end of the finger 2o ^a enters a recess in the ramp 16 ^{6 of} the primary sliding block 16 under the pressure of the spring 21 which is supported against the stop 58.

The task of the finger 2O ^a is the same as that of the bolt 20 shown in Fig. 4. In Figs. 5, 6 and 7 are channels for the lubrication ^{Uo of} the pivot axis of the lever 23, the sleeve 18 and the ramps of the primary and secondary sliding blocks are shown on the face of the chuck. The oil can be introduced into these channels through an oiler located at the front of the chuck.

The lever 19 passes through the part 3 ^{a of} the body of the chuck and is pivotable about the axis 23, which is mounted in part 3 ⁰ . For this purpose, the two ends of the axle 23 are located in the radial bores of two crescent-shaped bodies 24 which enter bores 25 which are provided on both sides of the window 26 recessed in part 3 ″ for the end of the lever 19 to pass through. These crescent-shaped bodies are provided with a collar 24 "

404-

see by which they are held in their position in part 3 ^0. ,

The elongated, rounded end io. ^{a of} the lever 19 enters the diametrical cutout 27 ^{s of} a disk 27 arranged in a bore of the clamping jaw carrier 28. This jaw-bearing slides on the front of the part 3 ^a. The clamping jaw carriers are guided in the radial direction on this front side by segments 29 fastened on the front side of the chuck. The segments are fastened by bolts 30, their position being determined by centering pins 3.1. The jaw carriers, the front of which is corrugated and slightly receding from the front of the segments, are intended to accommodate the, for example, step-shaped jaws, denoted by 32, which are fastened to the jaw carriers by means of bolts 33, the latter in the T-shaped groove of the Clamping jaw carrier slidably arranged strips 34 are screwed.

As shown in Figs. 11 and 12, the jaw carriers 28 can be used as a collet clamping device for machining workpieces with small diameters. Each clamping jaw carrier receives at its end in its inner groove the shaft of a part 35 which is fastened with the aid of bolts 36 which are screwed into suitable threaded bores in the clamping jaw carriers. The parts 35 are intended to receive a collet set 37 of the desired diameter. Each insert jaw 37 is inserted into the free end of a part 35 and fastened with the aid of a bolt 38. As can be seen in FIGS. 11 and 12, each part 35 is supported against the end of a clamping jaw carrier, both on the rear part of the same at 35 "and against its side edges 35 ⁶ . The fastening organs are therefore not subjected to shear stress. Since the clamping jaw carriers of the chuck act in this way in the form of pliers, the front of the chuck is advantageously provided with a cover applied to the segments 29 so that the front of the chuck has no protrusions that could endanger the operator during operation of the machine tool.

The working principle of the chuck described above is as follows: If at standing or rotating chuck on the tube 10, for example, from left to right Directed thrust is exerted, so is, as already mentioned, the organ 4 with reference to the Body of the chuck moved in the axial direction.

During its movement, the organ 4 causes a radial movement of the sliding block through its ramp 15 ° 16 to the outside and thus a pivoting of the lever 19, through which each of the clamping jaw carriers 28 moved radially inward and thus the • clamping of the to be taken up by the chuck Workpiece is made possible from the outside.

As soon as the clamping element, for example the clamping jaw 32, comes to rest on the workpiece, the resistance to the movement of the lever 19 increases. ·

Since the ramp 15 ° has a steep incline, the sliding block 16 can no longer slide on this ramp, so that if a thrust force continues to act on the pipe 10, the organ 4 and the sliding block 16 move relative to the secondary block 17, which is fixed to the Sleeve 18 is connected to the lever 19, can be taken along to the right at the same time. Since the inclination of the ramp x6 ^a , which now acts on the lever 19, is much smaller, the lever 19 performs a smaller radial movement with the development of a much greater force. During this movement, the bolt 20 or the finger 56 easily emerges from its guide provided in the sliding block 16 while the spring 21 is compressed.

When the tensioning process is completed, the secondary sliding blocks ij are also clamped in the sliding block 16. Since the workpiece is now firmly held in the chuck, machining can begin.

To relax the chuck, an oppositely directed thrust is exerted on the tube 10, ie in the present case a thrust directed from right to left. During this return movement of the axially movable member 4, the sliding block 16 is initially released from the ramp 15 ″, while the sliding block 17 still remains jammed in the sliding block 16. As can also be seen, the opposite ramp 15 ^s simultaneously brings the lever back into its starting position. If there is no such opposite ramp, the levers 19 must be provided with return devices. As soon as the primary sliding block 16 has become free, the jamming of the sliding block 17 is released so that the spring 21 can relax and the bolt or bolts 20 returns to the seats in the sliding block 16, whereby the sliding blocks 16 and 17 are brought back into their central position .

When clamping from the inside, the process is the same, but each time in succession it is the ramps 15 ⁶ and i6 ^& that come into effect instead of the ramps I5 ^a and i6 ^a. It follows that the direction of movement of the tube 10 is reversed.

The chuck according to the invention has the advantage that the inner bore of the spindle is free remains, whereby the machining of long,. Through this hole guided rods is made possible. Since these rods have a small diameter, it is advantageous to insert them into the spindle bore through a Guide and center pipe of suitable diameter.

As Fig. 13 shows, the tube 39 can be provided with a threaded ring 40 attached to its end that the lock nut 11 for securing the < Tube 10 in ring 9 replaced.

In other cases, for example for series production, it can be advantageous to use the

To provide the chuck with an axial stop. This stop is, as in Fig. 9 and 10 shown, advantageously formed by a blind tube 41 which is provided with three tabs 41 ". These brackets are attached to the segment bodies by means of bolts 42 which can be screwed into threaded bores 43 29 (Fig. 3) attached. These threaded holes can also be used to attach serve to cover the front of the chuck certain cover plate.

To adjust the position of the pipe 10 with respect to the ring 9, the one shown in FIG. 14 can be used Double keys can be used. This key consists of a tube 44 that is attached to one of its Ends a washer 45 provided with teeth 45 °, the teeth 45 ° for engagement with am End of the ring 9 provided notches 48 are determined, and from a shaft 46, which is also carries a disk 47 which is provided with teeth 47 ** which cooperate with the notches 49 of the lock nut 11 or the threaded ring 40. Since the position of the ring 9 is determined by the rotation of the pipe section 44, when the pipe section 44 is attached to it by the

s5 handle is held, the shaft 46 for the Tightening the lock nut 11 can be rotated. The invention is of course not based limited to the embodiment described above, but can within their Changes within the framework, in particular through the use of technical equivalents.

Claims (4)

PATENT CLAIMS: i. Chuck for machine tools with an axially displaceable body, which acts in the direction of the axis via inclined surfaces on one ends of double-armed levers, each of which is rotatable about an axis that is tangential with respect to the chuck and with its other ends engaging clamping jaws that can be displaced in the radial direction , characterized in that the axially displaceable body (4) has inclined openings (15) with respect to the axis of the chuck, the boundary walls (15 ″, ΐ5 ^δ ) of which are tangential to the direction of rotation form parallel, opposite ramps between and opposite one another each of which a sliding block (16) that engages in an articulated manner on one of the levers (19) for moving the clamping jaws can be displaced. 2. Chuck according to claim 1, characterized in that the sliding blocks (16) themselves are again provided with an inclined opening with respect to the axis of the chuck, the boundary walls of which are tangential to the direction of rotation (i6 °, i6 ⁶ ) one opposite the first ramps have different slopes, and between and opposite 'which one on the lever (19) via a pivot articulated engaging second sliding block (17) is displaceable. 3. Chuck according to claim 2, characterized in that the second sliding block (17) via a spring-loaded, in the middle position with its convex face in a recess of the first sliding block (16) engaging bolt (20) is connected to the first sliding block. 4. Chuck according to one of the preceding claims, characterized in that the axially displaceable body (4) has outwardly protruding legs, on each of which one of the inclined ^{openings (15) provided with ramps (15 °, I5 6} ) is provided, and that the body is ^{guided with its legs between corresponding segments (3 6} ) of the chuck body is. ! th: Referred publications:
German patent specification No. 519 389. For this purpose 2 sheets of drawings 9613 A.5 $